The mongo shell will always produce the same set of random numbers if not seeded.

$ ~/mongodb/3.1.7/mongo --nodb
MongoDB shell version: 3.1.7
> Random.randInt(1000000)
242578
> ^C
bye
$ ~/mongodb/3.1.7/mongo --nodb
MongoDB shell version: 3.1.7
> Random.randInt(1000000)
242578

Tests that use Random.rand() or Random.randInt():

• jstests/core/geo_array2.js
• jstests/core/geo_update_btree.js (also affects the parallel shell)
• jstests/core/geo_update_btree2.js
• jstests/core/remove9.js
• jstests/core/removec.js
• jstests/dur/manyRestart.js
• jstests/multiVersion/mixed_storage_version_replication.js
• jstests/noPassthrough/initial_sync_cloner_dups.js
• jstests/noPassthroughWithMongod/indexbg_drop.js
• jstests/noPassthroughWithMongod/mr_writeconflict.js
• jstests/noPassthroughWithMongod/remove9.js
• jstests/noPassthroughWithMongod/sharding_balance4.js
• jstests/sharding/geo_shardedgeonear.js
• jstests/slow2/remove_during_mr.js (also affects the ScopedThreads)

Tests that use Array.shuffle():

• aggregation/bugs/server6125.js
• sharding/key_many.js